Rnomson



(No Model.)

H. LEMP.

ELECTRICAL CONVERTER.

No. 403,541. Patented May 21, 1889.

Hermann/ 8771.70

@31 Strum Lu :4. PETERS. mm-mhb w. wml m. 91c- UNITED STATES PATENTOFFICE.

IIERMANN LEMP, OF LYNN, MASSACHUSETTS, ASSIGXCR TO THE THOMSON ELECTRICIVELDING COMPANY, OF MAINE.

ELECTRICAL CONVERTER.

SPECIFICATION forming part of Letters Patent No. 403,541, dated May 21,1889.

Application filed February i, 1889. Serial No. 298,657. (No model.)

To aZZ whom it may concern.- to a commutator after the fashion of thecoils Be it known that I, IIERMANN LEMP, a citiand commutator of aGramme armature.

zen of the United States, and a resident of In the accompanyingdrawings, Figure 1 Lynn, in the county of Essex and State of illustratesdiagrammatically the principle of 5 Massachusetts, have invented acertain new my invention. Fig. 2 is a side elevation of a and usefulImproved Converter, of which the Gramme ring and commutator with a mag.lollowing is a specification. netic bridge-piece carrying one of thecoils of My invention relates to the construction of the converter. Fig.3 is an edge view of the inductioircoils or converters, and to meanssame.

To for obtaining from the secondary a regulable Referring to Fig. I, IIindicates a core or current irrespective of the potential or curring ofiron, preferably laminated, and hav- 6o rent flowing 111 the primary.ing a connecting-piece of iron extending ra- The object of my inventionis to provide a dially across from one side to the other, (indisimpleand eitective form of converter espccated at M,) and also preferablylaminated.

15 cially adapted for obtaining currents of low The core or carrier IIis wound with coils, as

potential but large volume, suitable for use indicated, and the bridge Mis wound with in electric welding and other metal-working another set ofcoils, IV, which may be of a operations. number of turns and of propercross-section My invention provides a means for regnto give the desiredpotential in the secondary 2o lating the current on the secondary,especircuit. I

cially suited for use in those cases where the Let it be assumed thatthe current from primary is supplied from a constant potential anyalternating source is allowed to enter the source. set of coils on thecore II at point A and to The invention consists, essentially, in theleave such coils at the point 13. The result combination, with a core orcarrier of iron of will be, as in the Gramme armature, theformacircular, cylindrical, or endless form, upon tion of two circuitsor branches through the which one set of the coils is wound, of a magcoils and the production of poles at N S. 'Unnetic bridge-piece of ironconnecting the opder this condition the magnetic bridge M posite sidesof said. core and wound with the will have no lines of force passingthrough it,

0 other set of coils of the converter. Either as it joins points ofequalmagnetic potential,

set may be the primary; but I prefer to make and the coil \V willtherefore generate no cur- So the first-named set the primary and theset rents. If, however, the current were permitupon thebridge-piece thesecondary. Current ted to enter at A and leave at B, consequent ispassed through the primary in proper manpoles would be produced at N Sat the ter- 3 5 nor to form consequent poles at or near the minals ol'the bridge M, thus causing a large terminals of the bridge, and in orderto pronumber of lines of force to pass through said 8 5 vide forregulation I wind said coils. in a conbridge and generate a maximumcurrent in tinuous series and connect the series at inthe coil \V. If alarger number of points of icrvals to the plates of a commutator havingentrance and exit for the primary current 40 two brushes, by which thecurrent may be were provided, it is obvious that poles might passed intothe primary at any two opposite be produced at intermediate positions,each 0 points, thereby permitting the position of the position resultingin the production in the consequent poles with relation to thetermisecondary of currents of a strength between nals of the bridge tobe adjusted or varied, the maximum and the minimum. Such pro 45 so as toregulate the strength of current set vision is indicated in Figs. 2 and3, where the up in said secondary. series of coils wound on the core IIis con- The primary coils maybe wound in any denected at intermediatepoints to the blocks sired fashion; but I prefer to wind them 011 of acommutator after the manner of an orlhe circular core or carrier andconnect them dinary Grammc armature. Suitable adjustable brushes, 1) 1),bearing on said commumay be curved outward, as indicated in Fig.

3, to give room for the coils W.

It will be observed that in adjusting the I current in the secondary bythe above device the electrical resistance, as Well as the number ofturns in the primary, is exactly alike under all conditions, thusespecially adapting the device for use on mains of constant potentialwhere it is desired to obtain a regulable current of low potential fromthe secondary.

I do not limit myself to any particular manner of applying the coils tothe core or carrier; but they are to be connected to one another and toany suitable switch, so that consequent poles of north and southpolarity, respectively, may be produced at opposite sides of the core orcarrier and at the points thereof more or less remote from the pointsWhere the magnetic bridge touches the core or carmen It is obviously notnecessar that the core or carrier H should be of exactly circular form.

NVhat I claim as my invention is- 1. In an induction-coil or converter,the combination, substantially as described, of an alternating currentprimarily Wound on an endless core, a magnetic bridge joining the sidesof said core and carrying the secondary, I

and an electric switch connected with the primary coils for varying theposition of the poles of the primary with relation to the ends of thebridge.

2. In an induction-coil or converter, the combination, with a circularor endless iron core or carrier having one setof coils wound upon it, ofan iron bridge or connecting-piece joining opposite sides of saidcarrier and wound with a second set of coils constituting the primary orsecondary, as the case may be.

3. In an induction-coil or converter, the combination, with an endlesscore or carrier Wound with primary coils in series, of a stationarymagnetic bridge-piece, and an adj ustable commutator having blocks orplates connected in regular order to the circuit of the primary coils,and commutator-brushes for passing current through said primary in twobranches or circuits, as and for the purpose described.

4. A variable-current induction-coil or converter having a primarycircuit formed through a commutator and coils constructed after themanner of a Gramme armature, in combination with a secondary wound on aniron bridge-piece connecting opposite sides of the iron core for theprimary, as and for the purpose described.

Signed at Lynn, in the county of Essex and State of Massachusetts, this31st day of January, A. l). 1889.

HERMANN LEMP.

Witnesses:

ELIHU THOMSON, J. W. GIBBONEY.

